#include <cmath>
#include <string.h>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

int num[26];
int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    string src;
    getline(cin,src);
    memset(num,0,sizeof(num));
    for(int i=0;i<src.length();i++){
        if(src[i]>='a'&&src[i]<='z'){
            int pos=(int)(src[i]-'a');
            num[pos]++;
            continue;
        }
    }
    int odd=0,even=0;
    for(int i=0;i<26;i++){
        if(num[i]==0) continue;
        if(num[i]%2==0) even++;
        else if(num[i]%2==1) odd++;
        else ;
    }
    if(src.length()%2==0){
        if(odd>0){
            cout<<"NO"<<endl;
        }
        else{
            cout<<"YES"<<endl;
        }
    }
    else{
        if(odd==1){
            cout<<"YES"<<endl;
        }
        else{
            cout<<"NO"<<endl;
        }
    }
    return 0;
}
